1. The Field of the Invention
This invention relates to operating surfaces for the type of computer input device generally referred to as a mouse. More particularly, the present invention relates to pads which allow a user to operate a mouse with precision and ease.
2. The Prior Art
The fields relating to digital computer hardware and software have experienced tremendous expansion in recent years. In particular, the personal computer or microcomputer has made significant computing power and capabilities widely available.
As the speed, sophistication, and availability of computers has increased, various devices for improving the ease and speed of inputting information to a computer have been devised. Many of these methods and devices are "user friendly," in that they allow even the novice computer user to easily use a computer to perform useful tasks. Still further, even experienced and expert computer users are able to communicate with a computer faster and with greater ease than ever before using these newly developed methods and devices.
Such user friendly devices include transparent touch screen overlays, light pens, graphic tablets, joysticks, track balls, and mice. All of these devices were developed as alternatives to the "QWERTY" keyboard that had been the standard input device since the early days of digital computers. Of all the above-listed devices, the mouse has been determined to be the most efficient and also the most user friendly.
A mouse is a hand-held device operated on a flat surface which, in cooperation with the necessary computer hardware and software, allows the user to control the movement of a cursor or pointer on a computer display. For example, if the user desires to move the display pointer to the upper left of the display, the user merely properly orients the mouse on the flat operating surface (such as a table top) and pushes the mouse in the direction of the upper left corner of the display while watching the display. The pointer constantly changes its position to correspond to the relative change in position of the mouse. Thus, the user can guide the pointer to any position on the display by use of the mouse.
Use of a mouse can greatly increase the speed and ease of inputting commands to a computer. As an example, suppose that a user wanted the computer to erase everything that was found in a particular file that was presently open. Rather than typing a command on the keyboard (which may be just one of a hundred commands which must be memorized in order to efficiently use the computer) the user might move the mouse until the pointer on the display is adjacent to the word "erase" (or a stylized representation of a trash can) which might appear in the upper left corner of the display. Once the pointer is in position, the user would "enter" the command by depressing a button, or key, on the mouse and the computer would then proceed to erase that file.
As shown in FIG. 1, a typical mouse 10 has a generally mound-like body 14 to be grasped by the user and a control cable 32 connected to a computer. As can be seen in the cut away portion of FIG. 1, the most predominant component in the mouse is the track ball 28, which makes contact with and rolls upon a table surface 12 when the mouse 10 is moved across it. If the mouse 10 is to be used effective the linear movement of the mouse across the table surface 12 must be accurately translated into the rotational movement of the track ball 12. This can be frustrated by the fact that a work surface, such as table surface 12, will often include imperfections such as dents and cracks as shown at 34 in FIG. 1.
The rotational movement of the track ball 12 is converted into a corresponding electrical signal by the rotation of rollers 22, mounted on driving shafts 26, which in turn drive potentiometers 16 by way of interconnecting gears 18 and 20. The potentiometers 16 convert the rotational movement into a proportional electrical signal.
Mice using the scheme just described are generally referred to as mechanical mice. Other types of mice convert the movement of the track ball to an optical signal which is then converted into a corresponding electrical signal. Such mice are generally referred to optomechanical mice. Still further, some sophisticated mice do not employ any rotating tracking member, such as a track ball, but sense the direction and speed of movement of the mouse by other means. A brief review of various types of mice can be found in Teschler, L., "Interfacing Mice to Computers," 56 Machine Design 84 (1984).
The resolution of a mouse is critical in many applications. While some sophisticated mice are capable of resolutions of up to 1000 divisions per inch, most mechanical and optomechanical mice are capable of resolutions from 100 to 300 divisions per inch. A computer display is made up of thousands of image units termed "pixels." A pixel is the smallest indivisible point on a display which may be controlled, that is, turned on or off. Many high resolution displays, such as those used with computers intended for graphics generation, have a great number of pixels and a very high resolution. It is desirable that a mouse also have a high resolution so as to be capable of resolving many divisions per inch when being used with a high resolution display.
While mice are capable of achieving high resolutions, the work surface upon which mechanical and optomechanical mice are operated can have a profound effect on the resolution and the efficiency of the mouse. For example, if a work surface is imperfect it will not allow the tracking member of the mouse to maintain a one-to-one relationship between the linear movement of the mouse and the rotational movement of the track ball. Since few personal computer users work on geometrically perfect table tops, users often notice that the pointer moves erratically across the display.
The track balls used in mice are made of smooth or textured metal or may be coated with a rubber-like material. As can be appreciated, a spot of corrosion, or other imperfection, on the surface of the track ball can cause erratic pointer movement which is aggravating to the user. Similarly, an imperfect operating surface will cause the same aggravating erratic movement of the pointer. For example, a dusty, dirty, wet, or uneven operating surface will cause erratic pointer movement since the track ball is not able to maintain its rotational movement proportional to the linear movement of the mouse across the operating surface.
In an effort to solve the problems associated with imperfect work surfaces, mice have been operated upon pads placed on the work surface. Many of these pads, generally termed mouse pads, which are available in the prior art have operating surfaces that themselves contribute to erratic mouse operation. For example, some pads are covered with a coated fabric. Fabric often has an undesirable texture due to the uneven threads of which it is made. These tend to urge the track ball to rest at certain points on the pad and avoid others. Such a condition often causes user frustration, since the pointer seemingly "refuses" to position "itself" at the correct point when the track ball is stopped at some locations on the fabric type of pads.
Furthermore, mouse pads which are comprised of rubber and/or fabric covered rubber often are undesirable due to the fact that the operating surface this provided for the mouse is too soft. A soft operating surface requires the user to push the mouse with excessive force. Also, a soft operating surface can cause other difficulties.
For example, with many mechanical and optomechanical mice used on rubber and fabric pads, if excessive pressure is placed upon the housing of the mouse by the user to overcome the additional drag, the undersurface of the mouse may dig into the surface of the pad. Thus, a soft operating surface in mouse pads generally reduces the speed at which the user operates the mouse, both due to additional drag and to the underside of the mouse becoming caught in the soft material making up the pad.
Furthermore, mouse pads found in the prior art generally are provided with a porous operating surfaces which absorbs liquids. Thus, the material often used in the prior art mouse pads do not lend themselves to cleaning. As the mouse pad becomes soiled due to spills and user contact, it generally becomes unsightly and there is no practical method of cleaning it.
In general, there has been a widely felt need among users of mice for a mouse operating pad which alleviates the disadvantages associated with the previously available pads. The present invention solves the problems associated with the previously available pads and meets the needs of mice users.